Homeowner Rong Zhang said she heard a loud noise and her entire house shook. "We didn't know what was going on," she told KTVU. The ice didn't break the home's ceiling and no injuries were reported.

But authorities are still trying to figure out where the ice could've come from. The home is in the flight path of San Francisco International Airport, according to the San Francisco Chronicle, and Federal Aviation Administration officials are looking at radar data to determine if the ice fell from a passing aircraft.

FAA spokesman Ian Gregor said reports of falling ice are rare and only occur a "handful" of times in a year.

Officials told KTVU, however, that the ice was white and not blue, ruling out the possibility that it dropped from an airplane's lavatory.

Weather was also not a factor, according to KTVU—skies were clear that evening, and temperatures were in the 90s.

Scientists offer another possible explanation: There have been 40 cases worldwide in the last 13 years of large pieces of ice plunging from the sky, according to KTVU. It is a phenomenon called megacryometeors. One theory says it is a result of global warming, where the lower part of the atmosphere expands and rises, causing hail conditions without thunderstorms.

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Meanwhile, an exasperated Zhang is still seeking answers: "How did this happen?"